(NewsNation) — Idaho police may have more information on the murder of four students than they are releasing to the public, a former FBI agent told NewsNation.

Former FBI Special Agent Steve Burmeister spoke with “Morning In America” about the ongoing investigation into the murder of four University of Idaho students. As of Sunday, police have said they have no suspects in the case and have not recovered the weapon used in the killing.

“It’s a fine balance, when anytime you have investigators involved, that they’re trying to provide information to the public, yet at the same time, preserve the sanctity of that investigation,” Burmeister said.

One reason police may not release certain information, he said, is so they can use it to fact-check and verify witness statements.

Kaylee Goncalves, Madison Mogen, Xana Kernodle and Ethan Chapin were found murdered near campus on Nov. 13. The three women were roommates and Chapin was dating Kernodle. Two other roommates were in the house and were not harmed.

Police initially told residents of Moscow, Idaho not to be worried then backtracked and said they could not guarantee there was no risk to the community.

All four victims were stabbed in their sleep according to a coroner’s report. A 911 call was made from one of the surviving roommates’ phones, but police have not said who placed the call.

Among the information the police have made public is that the weapon is believed to be a Rambo-style knife and they do not believe the two living roommates were involved. Police have released a potential timeline of the victims’ movements the night of the murders as well as a video showing Goncalves and Mogen at a food truck.

But they haven’t released other information, including the 911 call.

“People always want to know and hear the actual call itself and allow themselves to make that determination,” Burmeister said of public requests for the call to be released.

He said it may include bits of information the police are holding back because they aren’t necessary for the public to know at this time.

“It’s a tough decision on the part of law enforcement as far as what they will provide to the public, I think they tried to provide as much information to protect the public,” he said.

Most recently, police have asked residents and businesses in a specific section of the city to come forward with any outdoor video footage taken from 3 a.m. to 6 a.m. on Nov. 13, even if there doesn’t appear to be any motion or content in the film.